Home Amplifiers Why Car Amplifiers Usually Have Higher Wattage Than Home Amps?

Why car amplifiers usually have higher wattage than home amps? - home amplifiers

I asked amplifiers in many shops, varies the output from 300 to 500 watts. But car amplifiers were 500 to 2000 watts - and are not big and not expensive compared to an amp .. Home Why? I want an amp for my 400 .... watts/12 buy "subwoofer for the home. Pleaseeeeee